Innervation of the lumbrical and interosseous muscles in hand: analysis of distribution of nerve fascicles and quantification of their surface projections

Abstract

We aimed to determine the surface locations of the nerve fascicles that innervate the lumbricals and interossei, re-examine the branching pattern of the deep branch of the ulnar nerve (dUN), and provide a clear description of their course. Eleven fresh-frozen adult cadaver hands were investigated. Nerve fascicles that innervate the lumbricals, interossei, and surface landmarks including the distal wrist crease and 2–5 proximal finger creases were marked by radio opaque fibers and subjected to X-ray. We analyzed the images and set a quadrant-linked hand surface. Subsequently, we measured the lengths of both axes and the coordinates of the branch locations in the quadrant. The surface locations of branches that innervated the lumbricals and interossei were clearly quantified. The branches of dUN exhibited a 4-group distribution pattern. Novel methods for quantitatively locating the surface anatomy of these branches and demonstration of a 4-group branching pattern of the dUN were established.

Keywords:

• Hand
• nerve fascicle
• lumbrical muscle
• interosseous muscle
• surface projection

Acknowledgments

The authors thank the following individuals for their assistance in various aspects of the project: Yong-qiang Kang, Jun Wang, Jun Gu, Tao-tao Hui, Peng Xu, and Jiong Yu.

Disclosure statement

Each author certifies that he or she has no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.